H.264/AVC, one of the standard specifications for image encoding schemes, applies a deblocking filter to a block boundary in units of blocks each containing 4×4 pixels, for example, in order to reduce image quality degradation due to blocking artifacts produced when encoding an image. The deblocking filter is highly compute-intensive, and may account for 50% of the entire processing load when decoding an image, for example.
The standards work for High Efficiency Video Coding (HEVC), a next-generation image coding scheme, proposes application of the deblocking filter in units of blocks each containing 8×8 pixels or more according to JCTVC-A119 (see Non-Patent Literature 1). The technique proposed in JCTVC-A119 increases the block size of the minimum unit to which the deblocking filter is applied. The technique also determines the need to apply the deblocking filter on a per-block basis, similarly to H.264/AVC.